Announcing a new lawsuit against California, U.S. Attorney Jeff Sessions called top officials an “embarrassment” in the most recent escalation of the battle between Sessions and the Golden State.

U.S. Attorney General Jeff Sessions has had the California grizzly in his sights. Now, capping off a year of state pushback against the federal government on everything from marijuana regulation to immigration, Sessions announced he will sue California over the state’s immigration laws, with scathing remarks that blasted recent immigration comments by top officials an “embarrassment” to the state of California.

In May, the Sacramento Bee wrote about how a showdown between California and the attorney general was inevitable. Kern County Sheriff Donny Youngblood told the Bee that federal justice officials and the liberal state were on a “collision course.” This is partly because of everything California represents to its detractors: environmental regulations, gun control, and hippies.And Sessions leans to the right not just of the state, but of many in his own party. (“He is an outlier in terms of how he thinks about drug policy even with the Republican Party,” Michael Collins, the deputy director for national affairs at the Drug Policy Alliance in Washington, told The Guardian last year.)

The state of California and its cities have been fighting Sessions and the Trump administration on issues across the board,but immigration has become the most contentious. The lawsuit, which was filed on Tuesday, sues California, Governor Jerry Brown, and the state’s Attorney General, Xavier Becerra. The suit alleges that three state laws passed in recent months—which limit the immigration information the federal government receives from state and local governments and local businesses, and prohibit new contracts for immigration detainers—are unconstitutional, and have made it impossible for federal agents to deport undocumented immigrants.

The messaging of the lawsuit also takes particular aim at one mayor, Oakland’s Libby Schaaf, who warned residents about an imminent Immigration and Customs Enforcement (ICE) raid—a move that ICE’s acting director compared to a “gang lookout yelling, ‘Police!’” On Wednesday, Sessions said while announcing the lawsuit: “So here’s my message to Mayor Schaaf: How dare you? How dare you needlessly endanger the lives of law enforcement just to promote your radical open borders agenda?”

He also slammed California Lieutenant Governor Gavin Newsom as an “embarrassment” for supporting Schaaf, to which Newsom had this to say:

Jeff Sessions just called me an embarrassment. A man whose legacy is targeting immigrants, re-waging the failed War on Drugs, sucking-up to private prison profiteers, and apologizing for white supremacists... I take that as a HUGE compliment.

There have been signs of a storm brewing.In January, the San Francisco Chroniclereported that U.S. immigration officials were preparing for the Trump administration’s biggest immigration enforcement action: a sweep inSan Francisco and other Northern California cities to arrest more than 1,500 undocumented people.

The sweep was in response to SB-54, which California Governor Jerry Brown signed in October. It bans state and local agencies from “holding” undocumented immigrants for U.S. Immigration and Customs Enforcement (ICE) and prevents local law enforcement agencies from asking about someone’s immigration status. The bill also prohibits creating new contracts or expanding old ones to use California law enforcement facilities as immigration detention centers.

Cities are changing fast. Keep up with the CityLab Daily newsletter.

Although Brown wrote in a signing message that “[SB-54] does not prevent Immigration and Customs Enforcement of the Department of Homeland Security from doing their own work in any way,” the Trump administration still believed the liberal state was thumbing its nose at the federal government.

In response to the sweep, the Oakland City Council voted to end all cooperation with federal immigration agents. And in a statement to the San Francisco Examiner, acting Mayor of San Francisco London Breed stood her ground. “We will not turn our backs on the people of this city because of threats from the Trump administration,” she said. “We will continue to fight in the courts to ensure that the hardworking immigrants of this city and state are protected.”

It will be a fight on multiple fronts, and the Justice Department isn’t the only one using the courtroom as a battleground. In 2017, California Attorney General Xavier Becerra’s office filed 24 lawsuits against the federal government, on issues ranging from education to birth control. But there are two key topics that have put the state and Sessions in close, warring proximity: drugs and immigration.

Going for the Gold(en State)

The decisions to target California in the immigration raid and, now, the lawsuit, are not just strategic, but symbolic. The Golden State is not the only one pushing back against the administration’s immigration stance. Many cities have taken up that mantle, and in August, Illinois Governor Bruce Rauner signed the Illinois Trust Act. Also known as SB-31, the bill restricts local law enforcement from arresting or detaining people based solely on their immigration status, and from handing undocumented immigrants over to federal immigration agencies without a judicial warrant.

If the Trust Act isn’t a twin of the California bill, it’s at least a close relative. But the Illinois bill received comparatively less press—and less backlash. Federal officials did not go on television calling for Illinois’ blood.

It’s true that Illinois was careful to make clear that the Trust Act was not a “sanctuary state” policy. “Those words can be inflammatory and can suggest that an organization or law enforcement is going to turn their back on federal law, and that’s not true,” Ed Wojcicki, the executive director of the Illinois Association of Chiefs of Police, told CityLab in advance of the bill’s signing. Wojcicki praised the bill, which he said would encourage “anyone living in Illinois [to] feel comfortable about calling the police and getting the service they need.”

But, at least according to NPR, Brown and other California lawmakers have been equally hesitant about using the term “sanctuary state,” well aware of all the ways in which the term is politically loaded. And yet that reticence does not appear to have made any difference to Washington.

Disagreeing on Drugs

In addition to hating sanctuary city policies,Jeff Sessions really hates weed. “Good people don’t smoke marijuana,” he said at a Senate hearing in 2016. (In a now infamous exchange, he also once said of the Ku Klux Klan, “I thought those guys were okay until I learned they smoked pot”; he later said the remark was a joke.) Sessions strongly opposes marijuana legalization, so it is perhaps unsurprising that he is using his position to target the drug in states where it has been legalized: like California.

Recreational adult-use marijuana became legal in California on January 1. Despite the recent rescinding of the Cole Memo, an Obama-era directive that basically told federal officials to let marijuana be in states where its use was legal, California has shown no signs of backing down from its legalization of the drug. Referring to the issue, Gavin Newsom, California’s lieutenant governor, told The New York Times,“There is no question California will ultimately prevail.”

Farimah Brown, Berkeley’s city attorney, wrote in an statement to CityLab, “As a general matter, the City of Berkeley is committed to implementing the voter adopted propositions relating to cannabis. The rescission of the Cole memorandum does not alter this commitment.” In the past, both Berkeley and neighboring Oakland have gotten involved in federal lawsuits to protect marijuana dispensaries.

Marijuana isn’t the only drug-related issue on which Sessions and the state of California don’t see eye to eye. In May, Sessions issued a memo ordering federal prosecutors to pursue the harshest sentences available for low-level nonviolent drug offenders.

U.S. Senator Kamala Harris, who has served as a California prosecutor, district attorney, and the state’s own attorney general, condemned the move. Harris said that Sessions holds “outdated and out-of-touch views” that will “take us back to the dark ages.” There is no love lost between Sessions and Harris: She criticized Sessions’ nomination for the position of attorney general and caused a kerfuffle when she was cut off in the middle of questioning Sessions during a Senate Intelligence Committee hearing. (Sessions, for his part, said that her rapid-fire directives made him “nervous.”)

The Border Wall and Immigration

Oakland and Berkeley have both passed measures that would withhold city contracts from any firms that take part in building Trump’s oft-referenced wall along the U.S.–Mexico border. Meanwhile, Becerra and the California Coastal Commission filed a lawsuit against the Department of Homeland Security and U.S. Customs and Border Protection in order to prevent the wall’s construction in the California counties adjacent to Mexico.

California was also the first state (joining a lawsuit with Chicago and San Francisco) to sue the Trump administration over its threats to defund “sanctuary” states and cities, complaining of federal overreach (often a red-state gripe). Becerra said that $28 million in government grants were at stake. And it was a California federal court that ruled that the Trump administration could not deny funds to cities and counties that chose not to enforce federal immigration laws.

Administration officials have also recently suggested that they would consider arresting the leaders of cities with “sanctuary” policies. California officials were hardly deterred by this; Oakland Mayor Schaaf announced that she was ready to go to jail to protect her city’s status before later warning residents about an imminent ICE raid.

Many of the recent policy choices of the Trump administration have put it squarely at odds with the Golden State. The insurgence isn’t always unchecked—although California fought Trump’s travel ban, the Supreme Court still allowed the ban’s third iteration to go into effect. Regardless, the state doesn’t just stand for what Sessions hates: It also represents a stubborn resistance to his power.

The new lawsuit could portend more unfriendly fire waged in the courtroom between California and the federal government. When the Department of Justice or the Trump administration at large puts forward a policy the state doesn’t agree with, it makes no bones about its displeasure—and its intention to rebel. Which, in turn, leads the federal government to take punitive measures. But if this is a game of chicken, it’s unclear who will win. California has certainly given no sign that it intends to back down.